Measurement of Analyte with an Acoustic Wave Sensor

Abstract

A sensitive assay for an analyte employing an acoustic wave sensor. A label which has a higher dissipative capacity than the analyte is adhered to the sensing surface of an acoustic wave sensor through the analyte such that the body of the label is spaced apart from and anchored to the surface of the acoustic wave sensor by a distance of 15 to 250 nm. The change in the energy losses of the acoustic wave when the label binds to the sensing surface is used to measure the presence or amount of the label. A substantial improvement in the detection limit of the label is obtained. The analyte may for example be a nucleic acid and the label may for example comprise liposomes.

Description

REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to Patent Cooperation Treaty (PCT) application having PCT application Ser. No. PCT / EP2016 / 065612, titled “Measurement of Analyte with an Acoustic Wave Sensor,” filed 1 Jul. 2016, which claims priority to Great Britain application number 1511687.4 filed 3 Jul. 2015, wherein both of the foregoing priority applications are hereby incorporated by this reference in their entireties.FIELD OF THE INVENTION[0002]The invention relates to the field of measuring the presence and / or amount of an analyte using an acoustic wave sensor.BACKGROUND TO THE INVENTION[0003]The present invention addresses the problem of measuring a small amount of an analyte, such as a nucleic acid, protein or hormone, in a sensitive, simple and cost-effective way. Measuring includes detecting the presence (versus absence) of the analyte, which is typically a binary measurement with a yes or no outcome, or making a quantitative measurement of...

AI Technical Summary

Benefits of technology

The patent describes a method to improve the sensitivity of measuring a certain substance in a liquid using an acoustic wave sensor. This is achieved by using a label that has a greater ability to dissipate energy than the substance itself. When the label binds to the substance, it causes a measurable change in the sensor that is above the detection limit of the sensor when the substance alone is measured. The substance can be any type of DNA fragments produced by enzymatic amplification or hybridization, which can bind to the sensor surface through covalent bonds. This method eliminates the need for a separate recognition molecule and makes the measurement more robust.

Problems solved by technology

Still, today, while PCR represents the ultimate in terms of sensitivity, it has significant drawbacks including complexity, sensitivity to contamination, cost and lack of portability (Rosi, N. L.; Mirkin, C. A.; Nanostructures in Biodiagnostics, Chem. Rev. 105:1547-1562 (2005)).

In some settings, PCR bias can cause 10 to 30-fold differences in amplification efficiency which could result in underestimation or failure to detect mutations.

In the case of heterogeneous samples where rare mutated sequences exist amongst abundant wild-type sequences, the PCR may be unable to amplify sufficiently these rare targets.

Furthermore, non-specific PCR inhibitors, including heparin, and uncharacterized components are sometimes present in samples from patients which may lead to undesired results such as mis-priming and inhibition.

However, this impressive performance, similar to that obtained with PCR, does not come in a simple format; it involves cumbersome and lengthy procedures such as the use of exogenous surface-modified components and multi-step amplification and detection schemes.

However, the mechanism by which acoustic energy is dissipated when biomolecules are attached to the device surface is still unclear and unexploited in clinical applications.

Briefly, a drag force is produced by oscillating biomolecules (attached to the surface via a single point) in the surrounding liquid and this is energy consuming.

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